The story of Lonely Seventeen centers on Danmei, a seventeen-year-old high school girl who comes from a wealthy family. The film begins with Danmei inviting her cousin, who is also her sister’s fiancé, Feng Ze (Ke Jun-Xiong), to come over to her place on a rainy night. However, Feng Ze secretly visits his mistress first and gets seriously wounded after a fight with the woman. When he tries to make a second stop at Danmei’s place, he loses control of his car and is killed in a car accident. After the death of Feng Ze, Danmei and the mistress start to behave strangely, and both of them are sent to the same mental health institute after their emotional breakdown. Centering on the two women’s mental disorder, the film reflects Bai Jingrui’s fascination with the social construction of the illness.